644232645 has 72 divisors (see below), whose sum is σ = 1355567616. Its totient is φ = 281679552.

The previous prime is 644232577. The next prime is 644232661. The reversal of 644232645 is 546232446.

644232645 is a `hidden beast` number, since 6 + 4 + 4 + 2 + 3 + 2 + 645 = 666.

644232645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644232645 - 2⁸ = 644232389 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 44364 + ... + 57066.

It is an arithmetic number, because the mean of its divisors is an integer number (18827328).

Almost surely, 2^644232645 is an apocalyptic number.

It is an amenable number.

644232645 is an abundant number, since it is smaller than the sum of its proper divisors (711334971).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644232645 is a wasteful number, since it uses less digits than its factorization.

644232645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12751 (or 12741 counting only the distinct ones).

The product of its digits is 138240, while the sum is 36.

The square root of 644232645 is about 25381.7384156405. The cubic root of 644232645 is about 863.6694860108.

It can be divided in two parts, 644 and 232645, that added together give a square (233289 = 483²).

The spelling of 644232645 in words is "six hundred forty-four million, two hundred thirty-two thousand, six hundred forty-five".